LM3570 Datasheet | National Semiconductor

LM3570 Low Noise White LED Driver System July 2004 LM3570 Low Noise White LED Driver System General Description The LM3570 device provides a plete LED driver solution for wireless handsets and other portable devices using a display and keypad. With three constant current sources, up to three white LEDs can be used for display lighting with excellent current matching (0.3% typ.). The regulated 4.35V output voltage is perfect for driving auxiliary keypad LEDs in voltage mode. The LM3570 utilizes a high efficiency 3/2 CMOS chargepump with a pre-regulation loop that minimizes conducted noise on the input. It accepts an input voltage range from 2.7V to 5.5V and maintains a constant current...